In X-ray analyzers, i.e., X-ray diffractometers, fluorescent X-ray devices, small-angle X-ray scattering devices, and the like, X-rays generated from an X-ray generator irradiate a specimen targeted for analysis. In a typical X-ray generator, electrons generated from a cathode are made to collide against the surface of an anode, thereby generating X-rays from the surface of the anode. The region where the electrons collide, i.e., the region where X-rays are generated, is typically called the X-ray focal point.
The wavelength of the X-rays generated from the anode is determined by the material of the region that corresponds to the X-ray focal point in the anode. Known materials for anodes include Cu (copper), Mo (molybdenum), Cr (chromium), Co (cobalt), and the like. The material of the anode, is selected, as appropriate, according to the type of analysis that is to he carried out. For example, in a case in which structural analysis of a protein is to be carried out by an X-ray diffractometer, a plurality of materials selected from the above plurality of mate would be employed.
Conventionally, according to Patent Literature 1, there is disclosed in FIG. 1 of the Literature a configuration for using negative pressure produced by suction of sir to move the anode housing that supports the anode, and by this movement selectively arranging an X-ray generation -zone of one kind from among two kinds on the anode, to a position facing the cathode.
In this conventional device, a gap is formed by means of two wall surfaces, namely, a wall surface of a casing that houses the anode and a wall surface of a protruding member that extends from the casing, and within this gap is arranged a flange that extends from the anode housing. The components are then arranged so that the cathode and one of the X-ray generation zones are facing when the flange of the anode housing has abutted the wall surfaces, and the cathode and another one of the X-ray generation zones are facing when the flange of the anode housing has abutted the wall surface of the protruding member.
That is, in the X-ray generator of Patent Literature 1, two X-ray generation zones are respectively arranged at positions facing the cathode, while using the wall surface of the casing and the wall surface of protruding member as stoppers. However, with this method, there is a problem in that for an anode equipped with three or more X-ray generation zones, any one of the X-ray generation zones thereof cannot be stationed at a position facing the cathode.
According to FIG. 8 of Patent Literature 1, there is disclosed a method whereby a stopper device for an anode equipped with three or more X-ray generation zones is configured by placing the distal end of a check bolt in abutment against a flange of the housing to station any one of the X-ray generation zones at a position facing the cathode. With this method, the amount of threading of the check bolt is adjusted to change the position of the distal end, so that the position at which the anode stops can be changed.